SU1190502A1 - Device for generating pulses with difference frequency - Google Patents

Abstract

1. DEVICE FOR THE FORMATION OF PULSE-DIFFERENT FREQUENCY, containing three triggers, the information input of the first trigger connected to the first input bus and the information input of the second trigger, the synchronization input of which is connected to the second input bus, different in that, in order to improve the reliability of the device , two elements are introduced into it, a delay element and a block for determining the sign of the frequency difference, the first input of which is connected to the information input of the second trigger, the synchronization input of which is connected It is connected to the synchronization input of the first trigger, the direct outputs of the first and second triggers are connected to the first inputs of the first and second elements, respectively, and the inverse outputs of the first and second triggers are connected to the second inputs, respectively. the second and first elements And, the outputs of which are connected respectively to the single and zero inputs of the third trigger, the direct and inverse outputs of which are connected respectively to the first I output ine and a third input for determining the sign of the frequency difference block, whose output is connected to the second output bus. SO about eaten about 1C

Description

2. The device according to claim 1, characterized in that the frequency difference sign determining unit comprises four flip-flops, two elements And a delay element, wherein the information input of the first flip-flop is connected to the second input of the frequency difference sign determining unit and the information input of the second flip-flop synchronization of which is connected to the first input of the block determining the sign of the frequency difference and through the delay element to the synchronization input of the first trigger, the direct outputs of the first and second triggers are connected to the first inputs

the first and second elements, respectively, and the inverse outputs of the first and second triggers are connected to the second inputs of the second and first elements, respectively, whose outputs are connected to the single and zero inputs of the third trigger, respectively, the inverse output of which is connected to the synchronization input of the fourth trigger, whose information input connected to the third input of the unit for determining the sign of the frequency difference, the output of which is connected to the output of the fourth flip-flop.

The invention relates to a pulse technique and can be used in digital systems of automatic control and regulation, as well as in devices for linearizing the characteristics of frequency data. The purpose of the invention is to increase the reliability of the device by eliminating malfunctions at input pulse sequences that are close in frequency. FIG. 1 shows a functional diagram of an apparatus for generating differential frequency pulses; in fig. 2 - time diagrams that show his work. A device for generating differential frequency pulses contains triggers 1-3 two elements 4 and 5, a delay element 6 and a frequency difference sign determining unit 7, the information input of the first trigger 1 connected to the first input bus 8, and the first input of the difference sign determining unit 7 frequency and with the information input of the second trigger 2, the synchronization input of which is connected to the second input bus 9, to the second input of the block 7 for determining the sign of the frequency difference and through the delay element 6 to the synchronization input of the first trigger 1, direct outputs The first 1 and second 2 flip-flops are connected to the first inputs of the first 4 and second 5 AND elements, respectively, and the inverse outputs of the first 1 and second 2 triggers are connected to the second inputs of the second 5 and first 4 AND elements, respectively, whose outputs are connected to one and zero respectively the inputs of the third trigger 3, the direct and inverse outputs of which are connected respectively to the first output bus 10 and to the third input of the block 7 for determining the sign of the frequency difference, the output of which is connected to the second output bus 11. The detection unit 7 the sign of the frequency difference contains four trigger 12-15, two elements 16 and 17 and the delay element 18, and the information input of the first trigger 12 is connected to the second input of the block 7 for determining the sign of the frequency difference and the information input of the second trigger 13, the synchronization input of which is connected to the first input of block 7 for determining the sign of the frequency difference and, through a delay element 18 to the synchronization input of the first trigger, the direct inputs of the first and second triggers are connected to the first inputs of the first and second elements 16 and 17, respectively, and The tersky outputs of the first and second triggers are connected to the second inputs of the second and first elements 17 and 16, respectively, the outputs of which are connected respectively to the single and zero inputs of the third trigger 14, the inverse output of which is connected to the synchronization input of the fourth trigger 15, whose information input is connected to the third input unit 7 for determining the sign of the frequency difference, the output of which is connected to the output of the fourth flip-flop 15. A device for generating differential frequency pulses works as follows. Pulse sequences with frequencies fi and fa are fed to the input buses 8 and 9 of the device (Fig. 2a, b). The device is based on gating a pulse sequence with a frequency fi arriving at the D input of trigger 2, the leading edge of positive pulses of the sequence with frequency f2 arriving at the C input of trigger 2. At the output of the trigger 2, a signal is generated with a frequency equal to the frequency difference input pulse sequences. The operation of the device does not depend on the initial state of the triggers and on which of the input pulse sequences has a higher frequency.

When the device is in operation, when at the moment when a positive edge of a pulse sequence with a frequency f2 arrives at the C input of trigger 2, a positive polarity of the sequence with frequency fi acts on the D input of trigger 2, in which case a single state of trigger 2 will be detected or confirmed. If at this moment a negative polarity pulse of a sequence with a frequency fi acts on the D-input of trigger 2, then the zero state of trigger 2 will be established or confirmed (Fig. 2 d, g). Trigger 1 works similarly (Fig. 2e, and), the only difference is that its C-input receives a sequence of pulses with a frequency h delayed by a time equal to the delay value of delay element 6 (Fig. 2d). When the pulses of positive polarity coincide in time at the inputs of the element 5 at its output, a pulse of positive polarity is formed (Fig. 2g).

This pulse sets the trigger 3 to one state (Fig. 2 l, t) and a high potential is formed on the output bus 10 of the device. When the positive polarity pulses coincide at the inputs of the element 4 at the output of the latter, a positive polarity pulse is formed (Fig. 2k). This pulse establishes or confirms the zero state of the trigger 3 (Fig. 2 l, t) and a low potential is formed on the output bus 10 of the device. The change in the state of trigger 3, and consequently, the potential level on the output bus 10 of the device, occurs when at the moment the C-inputs of the flip-flops 1 and 2 arrive at the next positive edge of the pulse sequence with frequency f2 on the D-inputs of these triggers the polarity of the pulse sequence with a frequency f different from the polarity of the pulse of this sequence acting on the D-inputs at the time of arrival on the C-inputs of the previous positive edge of the pulse sequence with a frequency h- Thus, level of the potential on the output bus 10 of the device occurs at a frequency equal to the frequency difference of the compared pulse sequences fi and 2, ie with the frequency |.. fi-f

The combination of the trigger frequency difference between triggers 12-14, elements 16 and 17, and zadeozh element 18, which are part of block 7 for determining the sign of the difference in frequency, works similarly to that described. The difference in their work is that the D-inputs of the trigger 12 and 13 receive a pulse sequence with a frequency f2, and the C-inputs - a pulse sequence with a frequency fi. Therefore, in block 7, determining the sign of the frequency difference at the outputs of the flip-flops 12 (Fig. 2 n, p) and 13 (Fig. 2 m, n), the gating of the pulse sequence with the frequency f2 and the leading edge of the positive pulses of the sequence with the frequency fi occurs. the output of the trigger 14 (Fig. 2 y) occurs according to the signals from the outputs of the AND elements 16 and 17 (Fig. 2 s, o) with a frequency equal to the frequency difference of the compared pulse sequences f2 and fi, i.e. with frequency

5 | f2-fi The signal about the sign of the difference in frequency of the compared pulse sequences is formed at the output of the trigger 15 (Fig. 2f), which gates the signal with a frequency equal to | fi-f2 | at the D input of the trigger 15, positive

0 by the front of a signal with a frequency equal to | f2-fij arriving at the C input of the trigger 15. In this case, the single state of the trigger 15 indicates that the frequency fi is higher than the frequency f2, and the zero state of the trigger 15 indicates that the frequency fi is less than f2.

5 In the case of close values of frequencies and coincidence in time of the fronts of the input pulse sequences, the output state of triggers 1 and 2 may be ambiguous. However, the presence of delay element 6 in the device completely excludes

0 the possibility of simultaneous ambiguous output state of the triggers 1 and 2, and the elements 4 and 5 provide reliable switching of the trigger 3 with a frequency equal to the frequency difference of the input pulse sequences. For similar purposes

The delay element 18 (Fig. 2c) and AND elements 16 and 17, which are part of the frequency difference order definition block, serve.

The device allows to obtain with high reliability information about the frequency difference between two pulse sequences when the following conditions are met:

the frequencies of the input pulse sequences should differ by no more than 1.5 times;

2, the delay of the delay elements must exceed the maximum value of the difference between the periods of the input pulse sequences, but be less than the duration of the positive pulses of the input pulse sequences.

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Claims (2)

1. DEVICE FOR FORMING DIFFERENCE FREQUENCY PULSES, containing three triggers, wherein the information input of the first trigger is connected to the first input bus and to the information input of the second trigger, the synchronization input of which is connected to the second input bus, characterized in that, in order to increase the reliability of the device , two elements And, a delay element and a unit for determining the sign of the frequency difference, the first input of which is connected to the information input of the second trigger, the synchronization input of which is connected to to the input of the unit for determining the sign of the frequency difference and through the delay element to the synchronization input of the first trigger, the direct outputs of the first and second triggers are connected to the first inputs of the first and second elements And, and the inverse outputs of the first and second triggers are connected to the second inputs of the second and first And elements, the outputs of which are connected respectively to the unit and zero inputs of the third trigger, the direct and inverse outputs of which are connected respectively to the first output bus and to the third mu input of the unit for determining the sign of the frequency difference, the output of which is connected to the second output bus. FIG. 1> 2. The device according to π. 1, characterized in that the unit for determining the sign of the frequency difference contains four triggers, two elements And and a delay element, and the information input of the first trigger is connected to the second input of the unit for determining the sign of the frequency difference and to the information input of the second trigger, the synchronization input of which is connected to the first input unit for determining the sign of the frequency difference and through the delay element to the synchronization input of the first trigger, the direct outputs of the first and second triggers are connected to the first inputs of the first and second, respectively of the And elements, and the inverse outputs of the first and second triggers are connected to the second inputs of the second and first And elements respectively, the outputs of which are connected respectively to the unit and zero inputs of the third trigger, whose inverse output is connected to the synchronization input of the fourth trigger, the information input of which is connected to the third the input of the unit for determining the sign of the frequency difference, the output of which is connected to the output of the fourth trigger.